Improvement in pressure-blower wheels



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patat entre Letters Patent No. 100,237, dated February 22, Y1870.

IMPROVEMENT 1N PRESSURE-BLOWER WHEELS.

Orv* The Schedule referred to l'n these Letters `Patent: and making para of the same.

To all whom it may concern Be it known that I, B. F. STURYEVANT, of Jamaica Plain, in the count-y of N orfol k, and State ofMassachusetts, haveinventedan Improvementin Blowerl Wheels; and I do hereby declare that the following, taken in connection with the drawings which accompany and form part of this specification, is a description of my invention sulicient to enable those skilled in theart to practice it. v f In those centrifugalblowers the outlets of which are contracted or obstructed 'as in blowers used for forcing air into cupola-furnaces, &c., the escaping air is mailitained under considerable pressure, such as is indicated by its sustaining a eolumlrof--water about twelve inches high, more or less, in the tube ot' an indicating pressure-gauge, said pressure being necessary for the proper pertbrmance of the work to be done by the blower.

In the blast-wheels of centrifugal blowers as heretofore constructed and acting to exp'el air under considerable pressure, a portion of the effective power of the blower is lostby reason of intermittent elastic reactions of the outgoing current of nir, which causes the air to shoot backwardat intervals between the plateshroudings of the fan-blades. l

With a viewfto the improvement of the action of the pressure-blower, I have caused the. peripher'cs of the shroudings ot' the blast-wheel to extend overthe ends of the fans, and have perforated the shrouding for the escape of the air, so that all of the air within the wheel is rotated with the full velocity ofthe blastwheel, and is thrown out therefrom with the centrif-l ugal force due to the speed of the wheel at its circumference. I x

The peripheral part of the shrouding ofthe blastwheel serves to separate the air in the wheel from the air in theblo'wer-case. In the blast-wheel the pressure of the air is greatest next to the shrouding at the largest diameter of the wheel, and diminishes in pressure toward the center of the blast-wheel, while in the blower-case and the pipe therefrom, leading tothe contracted discharge opening, the pressure ofthelar equals within a slight fraction the greatest pressure of the air within the blast-wheel.

The slight excess of pressure within the peripheral and peribrated part of the blast-wheel shrouding over the pressure in the blower-ease and outlet-pipe is due to 'the presence of the shrouding which forms aboundary, through which air of superior pressure is thrown by centrifugal force, preventing elastic reactionof the air from entering the blast-wheel through the perforations in the shrouding, so that by continuing' the A shroudiug of a blast-wheel over the ends of the fans or blades of the wheel, and by peribrating the shrouding as described, I obtain the maximum of force with the minimum of the blast-wheel.

The object of lmy present invention is to so con-Y struct a pressure-blower wheel as to prevent access of air to the blades or fans by reaction or recoil from the outlet-pipe, such reaction being wasteful of. power and injurious to the proper pertbrmance ofthe blower,v

which, to produce the best effect, should be protected from such reaction; and y' -My invention consists in afan-wheel, the shroudings of which are extended over the ends of the fans or blades of the wheel, and are pierced with suitable holes, slits, or other openings, the aggregate area-of which issutlicient'for the outlet of the air tion by the wheel under pressure. K

In the drawings I have shown my invention in two modifications. VIn Figure 1, my invention is shown vin section, and in Y y Figure 2, in elevation. l Y

In both of said figures two wheels are `shown for use in a blower ease, the wheels being the saine except in the form of 'the openings-made in the periphery of theshrou'dings.

Tile wheels are made 'upof three spiders,a a l), rings c c fans`or blades (I, and shroudingsj.

The spiders a a are cast into-or are'otherwise iixed to the rings c, and thespider b has attached to its arms the fans or blades d, which are also connected at their edges to the shroudings.

The .shroudings are thin curved plates, which are joined to' the rings c, and at their peripheries convergetoward each other, and meet, and are joined together. .The shroudings are pierced at their peripheries with numerous holes, which -may be made by punching or 'drilling, as shown on the left of the drawings, or the metal of the shroudings may be simplycut through and displaceihas shown at the right of the drawings, or the holes through the shroudings may be madeas narrow slits, or of any other suitable form, care being taken to have the aggregated area of the openings suliicielnt to let the air freely out from. within the fan,

underln'essure.

I claim a blast-wheel having a series of peripheral outlets, substantially as and for the purpose specified.

Also, a blast-wheel in which the sideshrolnlings are continued by deflect-ion toward, and meeting or nearly l meeting in the center of the wheel, so as to form a peripheral shroudiiw.

'B. FQKSTURTEVANT,

Witnesses J. B. GnosBY, FnANCls GoULD.

power, and a uniform delivery fromY put in nio- 

